• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.804-815
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• 2019

Due to the depletion and environmental problems of fossil fuel, biomass has arisen as an alternative energy source. Biomass is a renewable and carbon-neutral source. However, it is moister and has lower energy density. Therefore, biomass needs thermal chemical conversion processes like gasification, and it does not only produce a flammable gas, called 'syngas', which consists of CO, H2, and CH4, but also some unwanted byproducts such as tars and some particulates. These contaminants are condensed and foul in pipelines, combustion chamber and turbine, causing a deterioration in efficiency. Thus this work attempted to find a method to remove tars and particles from syngas with a filter which adopts a pre-coating technology for preventing blockage of the filter medium. Hydrated limestone powder and activated carbon(wood char) powder were used as the pre-coat materials. The removal efficiency of the tars was 86 % and 80 % with activated carbon(wood char) coating and hydrated limestone coating, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.176-177
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• 2016

In the last few decades, attention toward atmospheric pressure plasma (APP) has been greatly increased due to the numerous advantages of those applications, such as non-necessity of high vacuum facility, easy setup and operation, and low temperature operation. The practical applications of APP can be found in a wide spectrum of fields from the functionalization of material surfaces to sterilization of medical devices. In the secondary battery industry, separator film has been typically treated by APP to enhance adhesion strength between adjacent films. In this process, the plasma is required to have high stability and uniformity for better performance of the battery. Dielectric barrier discharge (DBD) was usually adopted to limit overcurrent in the plasma, and we developed the pre-discharge technology to overcome the drawbacks of streamer discharge in the conventional DBD source which makes it possible to produce a super-stable plasma at atmospheric pressure. Simulations for the fluid flow and electric field were parametrically performed to find the optimized design for the linear jet plasma source. The developed plasma source (Plasmapp LJPS-200) exhibits spatial non-uniformity of less than 3%, and the adhesion strength between the separator and electrode films was observed to increase 17% by the plasma treatment.

• The KIPS Transactions:PartA
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• v.9A no.1
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• pp.129-136
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• 2002

JNI is a linkage method to other languages such as C/C++ which enables the Java to do the platform-dependent specific tasks and also, it can be used to reuse the existing libraries and programs. However, the complex and difficult steps are required to use JNI and it is Inconvenient to manipulate Java source and C/C++ source separately. We design and implement the JPP (Java Preprocessor) that enables the Java source and C/C++ source to handle in a same source file and reduces the required steps so as to use JNI easily.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.229-234
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• 2008

Korea Electric Power Corporation (KEPCO) has started the nation's first biogas-microturbine project in the city of Gongju as an effort to encourage the utilization of wasted biogas containing useful energy source in the form of $CH_4$. The goal of the project is to set up the biogas microturbine co-generation system for utilizing biogas as an energy source and improving the economics of the wastewater treatment plant. Wastewater treatment processes were investigated in depth to find improvement possibility. Changes in internal recirculation ratio and pre-treatment degree are needed to optimize plant operation and biogas production. Biogas pre-treatment system satisfies Capstone's fuel condition requirement with the test result of 99.9% and 90.2% of hydrogen sulphide and ammonia is removal performance. Installation of microturbine and manufacture of heat exchanger to warm anaerobic digester has been done successfully. Expected economic profit produced by the system is coming from energy saving including electricity 115,871kWh/year and heat contained in exhaust gas 579GJ/year.

• Journal of Industrial Technology
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• v.16
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• pp.13-24
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• 1996

This research aims to investigate the effects of an internal carbon source in the denitrification of piggery wastewater. In this study, the raw wastewater and the effluent from each of anoxic basin and anaerobic basin were used as the internal carbon sources. The experiments were carried out in batch system and the results are as follows ; i) Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. ii) The piggery wastewater contained about 60 percent of the readily biodegradable organic(RDCOD), which led to a conclusion that the raw wastewater could be used as the internal carbon source for the denitrification. For the efficient denitrification, pre-denitrification process was found profitable. iii) In denitrification, alkalinity production rates were in the range of 3.4 to $3.6mgCaCO_3/mgNO_3-N$. iv) The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.405-406
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• 2017

With the advance of ICT technology, E-Commerce is getting popular and used widely in daily life. Nowaday's commercial videos are also being used extensively to introduce commercial products to consumers. Most commercial companies are advertising their products on the internet with images and videos through online sharing sites. Putting pre-recorded videos online is easy, but it is difficult for sellers to interact with customers. Live Streaming is the transmission of digital content directly to the Internet in real time. Although there are many services available that provide live streaming on the internet, most are limited in the content they transmit. Building live streaming servers using open source projects will help users master the content which conveys to their customers. In this paper, we will consider implementation of Live Streaming Server for Video Commerce using Open Source.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.3
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• pp.387-398
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• 1996

In this study the cell arrival processes from pre-buffer into multiplexer for MPEG(Motion Picture Experts Group) coding video sources are analyzed with consideration of the traffic periodicity in frame level. The analysis is performed by introducing the two arrival models, that is, periodic on/off source model and periodic uniform arrival model. Modulated $N^*D$/D/1 queueing system is utilized in periodic on/off source model, while ${\Sigma}{N_i}^*D_i$/D/1 queueing system is used in periodic uniform arrival model. The presented models are validated by comparing with computer simulations. Numerical results for periodic uniform arrival model are shown to be very accurate, but those of periodic on/off source model are shown to be inaccurate as the number of sources are increased.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.211-213
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• 1999

This paper describes a new method for source current optimization of the electromagnetic devices. In a conventional method of current distribution optimization using design sensitivity based on a finite element method, position and width of coils are generally optimized under condition that shape of those is given. they cannot find the global minimum because the number of coils is pre-determined. To avoid this local minimum, source current region which is discretized uniformly is considered as design parameter. This discretized regions have zero or one current value during the optimization process. The proposed method is applied to magnetic resonance imaging(MRI) magnet.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.967-976
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• 2021

This study aimed to investigate the mechanism by which service companies transfer their services overseas and create new value while interacting with local characteristics. A narrative analysis method was used in a case study of Ajisen Ramen, a Japanese service company that created a Japanese-style ramen restaurant, which experienced rapid growth in China. This study analyzed the restaurant as global service innovation and constructed a causal mechanism to explain the resulting rapid growth. In the pre-entry stage, the tangible value source core service facilitated its successful overseas transfer. In the post-entry stage, value source core service standardization and value sharing were interrelated and locally accepted factors. Knowledge of the local characteristics influenced the local storefront format that allowed contact with local customers. This local front format made it possible to offer local customers new value. The global service innovation mechanism developed through this study reflects a causal diagram that correlated the theoretical concepts of these events.

• Journal of KIISE:Information Networking
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• v.34 no.2
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• pp.120-133
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• 2007

A multicast tree includes several, possibly a large number of, paths connecting source-receiver pairs, and network failure may disable part of the multicast tree. Reconstruction of the entire multicast tree to recover from a component failure is highly undesirable, because some group members have to suffer service disruptions even though the communication paths to/from them are not affected by the failure. To limit reconfiguration region and to maximize the likelihood of successful reconfiguration, we propose and evaluate a pre-planned reconfiguration policy for QoS multicast sessions. Specifically, we equip a reconfiguration path (RP) with each end-to-end path that connects a source-receiver pair in the multicast tree, and reserve resources in advance along the RPs. Efficient resource-sharing techniques are applied to reduce the amount of resources reserved for RPs but not used in the absence of failures. This way, we prevent uncontrolled competition among different multicast sessions which may simultaneously try to recover from failures. We evaluate the performance of the proposed scheme using simulation on randomly-generated networks. We use the shortest-path routing for QoS multicast sessions, and simulate both source-based and shared multicast trees. The evaluation results indicates that successful pre-planned reconfiguration can be achieved for all group members with reasonable overhead. Our scheme is also shown to adapt well to dynamic changes of group membership.